Reverse current circuit breaker



M r h 1949.- .1. F. OBRIEN ETAL 5 REVERSE CURRENT CIRCUIT BREAKER Filed Aug. 28, 1943 INVENTOR 1 RN 6- CAT-ALDO JOSFP O'BeIEN CEKQ A ORNEY 3 mm CIRCUIT BREAKER Joseph r. OBrien. 1m City, and John a. Oataldo, Summit, N. 1., "signers to John B. Pierce Foundation, New York, N. Y.. a corporation of New York Application August as, muse-m No. 500,334

2 Claims. (CL 200-106) The invention relates to electrical circuit breakers and particularly to reverse current circuit breakers, applicable particularly for direct current electrical circuits comprising an electric generator and a storage battery charged by the electric generator.

In particular, the invention relates to means to open the electrical connection of the generator to the main battery on reversal of flow of current, to prevent the generator from being driven,

, as a motor, from the battery.

It is an object of the invention, therefore, to provide means whereby a generator, for example, may be disconnected from the circuit upon a reversal of direction of current flow.

It is an object of the invention to provide a reverse current circuit breaker to automatically open a circuit upon reversal of the direction of flow of current.

It is an object of the invention to provide a reverse current circuit breaker which is simple in construction and operation, and which may be reduced to minimum size and weight, and low 7 cost.

In the accompanying drawings: Fig. 1 is a side elevation, partly in section, of

spective positive terminals of the generator and the storage battery.

The spring structure it is carried by a vertically slidable switch rod 18, a pilot end lid of which extends into a suitable guiding aperture in the base l2, as indicated in Fig. 1, and the upper end 2| oi which is journaled within a collar 21a formed at the upper end 2Ia of a supporting structure 2|. Intermediate the respective ends of the switch rod I! the switch rod is engaged by the hub of'a snap spring 22 which may be in the form of av spoked, dished" disc. see Fig. 4, the periphery of which is confined within a suitable rim 23 of the support 21. The snap spring is desirably of the type described and claimed in U. S. application Serial No. 441,382, now abandoned,

' filed May 1, 1942, by William E. Stilwell, Jr., en-

one form of reverse current circuit breaker embodying the present invention;

Fig. 2 is a horizontal sectional view taken on the line 2-2 of Fig. i;

Fig. 3 is a vertical end elevation, partly in section, on the lines 3-3 of Fig. 1;

Fig. 4 is a horizontal sectional view of the mechanically latched switch taken on lines 4-4 of Fig. 1;

Fig. 5 is a wiring diagram of the circuit breaker of Fig. 1.

Referring to the drawings, and particularly to the embodiment shown in Figs. 1 through 4, a mechanically latched reverse current circuit breaker embodying the present invention comprises a reverse current trip I0 and a mechanically latched switch ll suitably supported on a base I2 of insulation material and desirably contained within a suitable housing ll.

Positioned upon the base i2 is a main bus I5 of a direct current electrical circuit connecting a storage battery with the positive terminal of an electrical generator, as shown in Fig. 5. The bus I5 is not continuous, being provided with main contacts i8, i8 arranged to be closed by a movable contact in which cooperating contact points I1, I! are fixed to the ends of a springstructure It, as shown. Fig. 1 shows the circuit completed through the bus ll, thereby connecting the retitled Toggle springs, characteristics of said snap spring being that it has two positions of stable equilibrium, and it will throw from one to the other of said positions under the influence of movement less than that required to move the hub through its dead center position.

It will be understood that the switch rod l9 may be made in two parts, to permit. it to be passed through the spring 22.

At any suitable position along the length of the switch rod [9, said switch rod is cut to provide a sharp shoulder 24 for cooperation with the nose of a latch 25, as later explained. The upper terminus oi' the switch rod l9 carries a collar 20a which serves as a base for a spring biased manual control button 21, a downwardly extending spring portion 28 of which provides a spring detent which, when the button 21 is depressed, engages the adjacent surface of the latch 25 and rotates it about its pivot 29 in the direction of switch rod l8, to place the latch 25 in latching position relative to the shaft 19.

It will be noted from Fig. 1 that with the contacts l1, I! in closed circuit relationship with the contacts l8, IS, the spring I8 is stressed downwardly, thereby exerting an upward reactional force on the switch rod l9. In such stressedstate, the spring 18 is of suflicient force to overcome the stable equilibrium oi the snap spring 22; and were it not for the engagement of the latch 25 withthe shoulder 24, the spring 18 would move switch rod is upwardly, to cause the snap spring to throw to its opposite position.

The design of spring I8 is such, however, that its throw extent is sufllcient to move the switch rod 18 and hub of spring 22 enough to cause the snap spring 22 to complete its throw to its opposite position oi equilibrium, in which position,

shoulder 2| of switch rod I 9. Tore-close .the 5 circuit. the operator must press downwardly on the button 21 until the nose of the latch 26 again snaps over the shoulder at 24, whereupon the snap spring 22 is thrown to its Fig. 1 position and the contacts l6, H are again in closed circuit relationship. The upward reaction'of the spring v it maintains the engagement of latch 25 with shoulder 24.

The reverse current release It! comprises a permanent magnet 30. suitably mounted upon the base l2 and a soft iron clapper 3|, both faces of one end of which are provided with a layer 32 or non-magnetic material, said clapper 3| being fixed to the arm 33 of the latch 25. The latch assumes the characteristics of a pivoted bell crank 2 and permits the soft iron clapper 2| to be rotated within the gap between the poles of the permanent magnet 30. Pivotally secured to said clapper 8| so as to depend therefrom is a soft iron armature 34 which extends through a convolution 35 formed in the bus l5, as shown in Figs. 1 and 2.

The required direction of flow of current is from the generator to the battery, or in other words, in the direction indicated in Fig. 1 by the legend Required current flow", with such flow of 0 to move said contact means to open-circuit porent, the magnetic flux created about the convolution of the bus bar, through which the armature 34 passes, gives to the clapper 3! a. polarity opposite to the .magnetic polarity of the 1. .4 We claim:

l. A reverse current circuit breaker comprising in combination a base; load circuit conductors mounted on said base to locate their respective termini in close but spaced adjacency; contact means associated with said termini for connecting and disconnecting said load circuit conductors; switch rod means controlling said contact means; latch means for locking said switch rod means and said contact means in closed-circuit position; resilient means for moving said switch rod means to thereby move said contact means to open-circuit position; electromagnetic means for moving said latch means to its unlatching position relative to said switch rod means, said electromagnetic means comprising a magnet, an

arm of magnetizable material connected at one end with said latch means, means for movably mounting said arm to dispose its free end in a 0 path of movement between the poles of said magupper pole of the fixed magnet 30, thereby main- 5 I taining the latch 25 in its Fig. 1 position. If, 110wever, reverse current occurs, namely, a current flow from battery to generator, the polarity of the end 01 the clapper 3| is reversed so that its polarity is the same as the upper pole of magnet 4 30 in which circumstance the clapper 31 is repelled from such upper pole'and is thrown forcibly against the lower pole of the permanent magnet 26. The resultant rotation of the latch 25 clockwise about its pivot 28 forces the nose of the latch 25 out of engagement with the shoulder 24 in switch rod 19, permitting the spring I 8 to urge the switch rod 18 upwardly, whereupon the resulting action of the snap spring 22 completes the upward movement of the switch rod l9 to the contacts l6, 86 from the contacts i7, I], thus opening the bus l5 and disconnecting the battery from the generator. I

Whereas we have described our invention by separate reference to specific forms thereof, it will be -un-' net; and convolution means connected with said load circuit conductors and wound and mounted to control the direction of how of magnetic flux through said arm, whereby under the condition of flow of current reversely in said load circuit conductors, the free end of said arm is repelled by said magnet to thereby release said switch rod means from latching connection with said latch means and thereby permit said resilient means REFERENGES WED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 267,711 Peck et a] Nov. 21, 1882 308,610 Harvey Dec. 8, 1884 374,673 Griscom Dec. 13, 1887 463,192 Herrick et al Nov. 17, 1891 569,634. Gharky Oct. 20, 1896 630,539 Hewlett Aug. 8, 1899 728,752 Naphtaly et a! May 19, 1903 1,248,084: Curtis Nov. 27, 1917 1,611,741 Haiiburton Dec. 21, 1926' 1,947,236 Wall'e Feb. 13, 1934 2,166,327 Rypinski et a1 July 18, 1939 2,196,138 Bullard Apr. 2, 1940 2,276,537 Creveling Mar. 17, 1942 2,335,888 Stilweli Dec. 7, 1943 

